I bought a packet of hollyhock seeds and I'm ready to pot on or plant out. I don't know that colour flowers each will produce. I'd prefer to know what colours I have before I plant out. I'm guessing that my best option is to pot on, but what size pot should I use? Is a 30cm diameter pot adequate? If I plant out on a raised mound, would I be able to move the mound after it flowers? Does anyone know if they cope with root shock?

I think your best option will be to pot on to pots 25cm deep and greater than 18cm diameter. Hollyhocks can get to 1.5m.Then plant the pot into the garden soil in the location you want....if the colours are wrong you can lift the pot out and move.Once they have finished, remove from pot and plant into location for next season.Save seeds, label for colour and sow next Autumn.Classic old favourites!, plant with foxgloves and delphiniums!

Trying to raise them to flowering size in pots is not something I would do, GW, as they're likely to be far sturdier, longer lasting plants if they develop in the ground rather than pots.

If its absolutely imperative to do it, however, then the bigger the pots' diameter, the better chance the roots will have to spread adequately to support the plant and prevent it growing too spindly as it would tend to do in too small a pot.

As Daffy suggests, burying the pots would probably be the best option.

As an aside, if a particular colour is what you're after, some of the mail order seed companies offer individual colours or colour ranges. It's a long time since I have needed to order any, so am not sure of who might be your best option, but I'm sure if you decided to try this option in the future others would be able to help with suggestions.

Once planted and growing I would not move.Your options are to pot,(which I wouldn't do, either Pam) they will get over 1m in height, or plant, wait to flower, label for colour, collect seed and plant accordingly the following season. They look great a mixed group in the garden anyway.Or go to ebay and buy specific colour seeds.

I had one plant that survived to planting out, but it hasn't done much. It's only about 10cm tall (been in the ground almost a year if not more), although it has several leaves on it and generally it looks healthy. Maybe needs better soil. I'm having tree loppers over during the week to remove a boxelder maple and a conifer which are on either side of it, so it'll get more sun.